The main sources of plastic waste found in the ocean come from land and come from urban and storm runoff, sewer overflows, garbage, inadequate waste disposal and management, industrial activities, tire abrasion, construction and illegal dumping. Most plastic marine litter is the result of poor waste management. Continental plastic waste is thrown into the ocean by storms and river systems or is discharged directly into coastal waters. It has been estimated that at least 60% of the plastic that floats in the ocean is exported from coasts to open ocean waters.
It is estimated that between 1.15 and 2.41 million tons of plastic waste enter the ocean each year from rivers. Rivers are a major source of plastic waste in the oceans. We estimate that 1000 rivers, represented by red dots, are responsible for almost 80% of annual river plastic emissions worldwide, which range between 0.8 and 2.7 million metric tons per year, and small urban rivers are among the most polluting. The remaining 20% of plastic emissions are distributed in 30,000 rivers, represented by smaller blue dots.
Coastal terrestrial pollution (less than 50 km from the coast) is the main source of MPP and contributes about 9 million tons per year (Jambeck et al. Terrestrial pollution contributes 0.5 million tons, marine sources contribute 1.75 million tons and microplastics (there are great uncertainties about the main sources of marine plastics). Schmidt, Krauth and Wagner (201) use two models to estimate the amount of plastic that rivers export worldwide. One of them suggests that a significant part of terrestrial marine plastic waste enters through pathways such as stormwater runoff, wind dispersal and garbage, rather than through rivers.
The other suggests that rivers are the main source of terrestrial plastics that enter the sea, since eight large rivers in Asia and two in Africa represent about 90 percent of total river inputs. However, there is not enough data to estimate the proportion of marine plastic waste that results from the manufacturing and pre-consumption stages compared to the post-consumption stages. These higher-resolution data show that these factors, which affect the likelihood that plastics will not only reach the river but also the ocean, play a much larger role than the size of the river basin itself. This means that there is a lot of poorly managed plastic waste that can enter rivers and the ocean in the first place.
Climate, terrain, land use, and distances within river basins affect the likelihood that poorly managed plastic waste will be released into the ocean. There are many NGOs and non-profit organizations that rely on donations to develop their projects and research to reduce and eliminate plastic from the ocean. It provides free, open, regular and systematic reference information on the state, variability and dynamics of the blue (physical), white (sea ice) and green (biogeochemical) oceans in global oceans and European regional seas. The updated model then calculates the probability that plastic waste will reach a river and, later, the ocean.
The Copernicus Marine Service provides information on the oceans, including current data in near real time, that can help institutions create coherent plastic management strategies. If you live next to a sea or river, you can volunteer to pick up trash in your local community, thus eliminating plastics from waterways and preventing them from reaching the ocean in the first place. Numerical models estimate the routes of plastic, which sheds light on how plastic is distributed and shipped across the global ocean, thus revealing the areas of distribution and accumulation. .